Rollei´s answers were a 35mm SLR, an amateur compact camera and the SL66. The last of these was a 6 x 6 120-format SLR. After this, Rollei also built an electronic medium format system with the SLX, 6001, 6003, 6006, 6008 and Hy6 (all of which had no compatibility with the SL66).
The SL66 was a mechanical camera, inspired by the Hasselblad. Like the Swedish rival it was a cube with interchangeable lens, backs and finders, however, there was a major difference, the SL66 has a focal plane shutter.
While it had a limited 1/30 flash synchronization, this allowed for a different concept. Its’ lenses were simple with no shutter or focusing mechanism, as both of those are located in camera body. Focusing is made by means of an internal bellows which allows for close focus (1/1 with an 80 mm lens).
The range of lenses was similar to Hasselblads, mostly Zeiss-made (later they were Rollei-made, Rollei having bought the factory from Zeiss). The available lenses ranged from 30mm to 1000 mm. There is an ongoing dispute about relative performance of Rollei/Zeiss vs Hasselblad/Zeiss, but in real life I don’t believe anyone can see the difference.